Harmonic filter



FIG. 1 is a perspective view of a first embodiment of a harmonic filter of my design;

FIG. 2 is a front view thereof;

FIG. 3 is a left-side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a perspective view of a second embodiment thereof;

FIG. 7 is a front view thereof;

FIG. 8 is a left-side view thereof;

FIG. 9 is a top view thereof;

FIG. 10 is a bottom view thereof;

FIG. 11 is a perspective view of a third embodiment thereof;

FIG. 12 is a front view thereof;

FIG. 13 is a left-side view thereof;

FIG. 14 is a top view thereof;

FIG. 15 is a bottom view thereof;

FIG. 16 is a perspective view of a fourth embodiment thereof;

FIG. 17 is a front view thereof;

FIG. 18 is a left-side view thereof;

FIG. 19 is a top view thereof;

FIG. 20 is a bottom view thereof;

FIG. 21 is a perspective view of a fifth embodiment thereof;

FIG. 22 is a front view thereof;

FIG. 23 is a left-side view thereof;

FIG. 24 is a top view thereof; and,

FIG. 25 is a bottom view thereof. 

The ornamental design for a harmonic filter, as shown and described. 